Joe Petito, the father of missing "Gabby Petito, 22 , told CNBC he urged Gabby's fiance, Brian Laundrie, to work with authorities in their relooking for his daughter.
"Cooperate ... We have questions, maybe you have the answers, maybe you don't, but there is only one only way to find out, "Joe Petito said on The "News with Shepard Smith .
Investigators say Gabby Petito was living the "van life " with Laundrie, cruising the country in a 2012 Ford Transit van. has "started documenting their trips on YouTube is three weeks old, but her mother says she hasn't heard from Gabby since August 30th.
The couple left Petito's mother's home on Long Island on July 2 and arrived in Utah in August. Petito's mother said their next destination was Grand Teton National Park in Wyoming, but communication with herdaughter has become infrequent. She said there were no more phone calls and just one last text. Her family reported Gabby's disappearance to police over the weekend.
Police say Laundrie is safe at his family's home in Florida.
Laundrie 's attorney issued a statement " Tuesday saying: "This is naturally an extremely difficult time for the Petito family and the family Laundrie. ... On the advice of counsel, the Laundrie family remains in the background at this point and will have no further comments. "
The Host Shepard Smith asked Joe Petito about the statement.
"That 's four lines of crap, that ' s basically what I see," said Petito. "Are you telling me this is a very difficult time for you when your child is home, safe? I don't know where mine is, and I can't ask p questions.Why, or where, or how, or where to start? "
Lawyers for the Laundrie family did not respond to CNBC's request for comment.
Officials have said they were looking for Petito with the help of the FBI. Florida Police said the couple's van was at Laundrie's house.
"I'm doing everything I can to find her , because apparently ... Gabby's family side is the only one that doesn't care, "Joe Petito said.
Police are asking anyone with information about Gabby Petito's whereabouts to call Crime Stoppers at 1-800-220-TIPS.